/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ---------------------
 * EntityCollection.java
 * ---------------------
 * (C) Copyright 2002-2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 23-May-2002 : Version 1 (DG);
 * 25-Jun-2002 : Removed unnecessary import (DG);
 * 26-Jun-2002 : Added iterator() method (DG);
 * 03-Oct-2002 : Fixed errors reported by Checkstyle (DG);
 * 30-Jan-2004 : Added a method to add a collection of entities.
 * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0
 *               release (DG);
 * 18-Jan-2005 : Added getEntity() and getEntityCount() methods (DG);
 *
 */

package net.droidsolutions.droidcharts.core.entity;

import java.util.Collection;
import java.util.Iterator;

/**
 * This interface defines the methods used to access an ordered list of
 * {@link ChartEntity} objects.
 */
public interface EntityCollection {

	/**
	 * Clears all entities.
	 */
	public void clear();

	/**
	 * Adds an entity to the collection.
	 * 
	 * @param entity
	 *            the entity (<code>null</code> not permitted).
	 */
	public void add(ChartEntity entity);

	/**
	 * Adds the entities from another collection to this collection.
	 * 
	 * @param collection
	 *            the other collection.
	 */
	public void addAll(EntityCollection collection);

	/**
	 * Returns an entity whose area contains the specified point.
	 * 
	 * @param x
	 *            the x coordinate.
	 * @param y
	 *            the y coordinate.
	 * 
	 * @return The entity.
	 */
	public ChartEntity getEntity(double x, double y);

	/**
	 * Returns an entity from the collection.
	 * 
	 * @param index
	 *            the index (zero-based).
	 * 
	 * @return An entity.
	 */
	public ChartEntity getEntity(int index);

	/**
	 * Returns the entity count.
	 * 
	 * @return The entity count.
	 */
	public int getEntityCount();

	/**
	 * Returns the entities in an unmodifiable collection.
	 * 
	 * @return The entities.
	 */
	public Collection getEntities();

	/**
	 * Returns an iterator for the entities in the collection.
	 * 
	 * @return An iterator.
	 */
	public Iterator iterator();

}
